Statement on Dungeness B

Today, the BBC reported that the independent regulator, the Office for Nuclear Regulation, is intending to approve a variation in one of the safety regulations that govern the operation of EDF Energy’s Dungeness B power station in Kent.

The two Advanced Gas-cooled Reactors at Dungeness B, along with our other AGR power stations, are made up of thousands of graphite bricks. This graphite core acts as a moderator – something that slows down fast neutrons sustaining the nuclear reaction.

We know how graphite behaves over time, and expect to see cracks and a loss of mass as part of the normal ageing process. This is a phenomenon known about and anticipated for within the safety regulations.

Those safety regulations are set very conservatively, well within wider safety margins, so we can be absolutely confident that the reactors remain safe to operate even when they appear to be close to the current limit.

At Dungeness B, we have used the information from a continuing programme of monitoring, inspection and physical sampling of the graphite core to assess the state of the core. This knowledge feeds in to modelling and experiments which give us the knowledge to allow us to safely increase the limit of weight loss within the core from 6.2% to 8%.

As time goes on we will continue to carry out these experiments and will request further increases as appropriate. EDF Energy remains focused on achieving a ten year life extension for Dungeness B which we hope to confirm by the end of the year. To ensure that safety margins continue to be sufficient, we have developed a programme of modifications which will feed in to the plant lifetime extension proposals and enable safe operation to 2028.

As is normal practice, we have submitted all our findings to the regulator for them to assess and make a decision. The ONR has told the BBC that they anticipate approving the variation in the limit within the next few weeks.

We work continuously with experts and UK universities to understand how materials in our nuclear reactors change over time and how that will affect the stations’ operations. We regularly refine our own safety assessments as we uncover new information. We share our findings with the regulator and with the wider scientific community.

EDF Energy statement:

“The safety of the public and our employees is our overriding priority. EDF Energy takes a cautious approach, works closely with the regulator and operates with very conservative safety margins. We have stringent safety requirements. We carry out regular inspections, including of the graphite bricks that are part of the cores of the reactors.

We work continuously with experts and UK universities to understand how materials in our nuclear reactors change over time and how that will affect the stations’ operations. We regularly refine our own safety assessments as we uncover new information. We share our findings with the regulator and with the wider scientific community. We also share them with the local community around each of our stations.

Nuclear power provides the UK with almost 20% of its electricity, and EDF Energy is making big investments to safely extend the lives of its 15 nuclear reactors.”